Questions tagged [unit-systems]

Questions that involve the choice of a system of units for measurement or calculations. For example, metric, U.S. customary, or Imperial units.

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Did von Braun ever have issues with the imperial unit system?

In Nazi Germany, von Braun and his colleagues which would then go on to work in the US, surely worked with metric units. Coming to the US, I can imagine they would have had to adjust to the imperial ...
Sebastian's user avatar
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1 vote
1 answer

What are the units for the orbital period equation?

I'm trying to find the time taken for a Hohmann transfer orbit. I've tried using all three of these equations, but when compared against known periods they all evaluate to the same wrong answer, 100 ...
user36065's user avatar
3 votes
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Are there examples of errors caused by the use of two English units?

The Mars Climate Orbiter was infamously lost because of software which used metric units in some places and U.S. Customary units in other places, without conversion factors. The incident is discussed ...
DrSheldon's user avatar
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6 votes
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How is foot-pounds of energy defined?

Tom Lodgson's classic textbook Orbital Mechanics: Theory and Applications frequently measures energy in foot-pounds, which I'd always thought to measure torque. The book doesn't define it. Is it the ...
Camille Goudeseune's user avatar
11 votes
2 answers

Why was the LRV's speed gauge displaying metric units?

In the question Why did NASA use U.S customary units? it was basically stated in the answers that even when metric units were used "internally" (e.g. the AGC), the units presented to the astronauts ...
DarkDust's user avatar
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2 votes
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Was Arthur J. Schwaniger one of very few US born NASA scientists using metric units?

Free-return trajectories were studied by Arthur Schwaniger of NASA in 1963 with reference to the Earth–Moon system. Those trajectories were used for the first Apollo missions. Mr. Schwaniger, who ...
Uwe's user avatar
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8 votes
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Which unit system was used by german rocket scientists at NASA for calculations?

There were numerous german rocket scientists at NASA, see wikipedia 1, 2. They were used to the metric system which they used when working for the V-2 at Penemünde. But what unit system did they use ...
Uwe's user avatar
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42 votes
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Why did NASA use U.S customary units?

NASA was using U.S customary units (inches, feet, nautical miles, pounds, tons, US gallons etc.) during the Mercury and Apollo programmes, and beyond. There are significant disadvantages to using U.S ...
user's user avatar
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4 votes
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What set of units does the Orion capsule cockpit instrumention use?

Shuttle was English, ISS is metric. What's Orion? For example: What units are inertial velocity displayed in?
Organic Marble's user avatar
4 votes
1 answer

Martian Names for the Year and Month Time Units

A Martian day unit is called a Sol. A week is supposedly still 7 days/sols. Have there been any (real or fictional) suggestions for new names for other time units like the Martian year? How about ...
Adi Shavit's user avatar
36 votes
4 answers

Why wasn't the Mars Climate Orbiter's fatal error caught prior to launch?

The Mars Climate Orbiter failed in 1999 due to: ground-based computer software which produced output in non-SI units of pound (force)-seconds (lbf·s) instead of the SI units of newton-seconds (N·s) ...
pacoverflow's user avatar
27 votes
1 answer

ISS nuts and bolts; Metric, SAE or both?

The International Space Station (ISS) is a joint construction of many countries around the world. Most of whom use the metric system for measuring including sizing of bolts, nuts and fasteners. ...
James Jenkins's user avatar
13 votes
1 answer

Did NASA use metric units for the Mercury missions?

Did NASA use metric or English units for Project Mercury? For example, did they measure delta-v in meters/second or in feet/second?
Joe's user avatar
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